1. Field of the Invention
The present invention relates to a mobile communication terminal, and more particularly, to an antenna apparatus for reducing user exposure to electromagnetic radiation generated from the mobile communication terminal.
2. Description of the Related Art
As mobile communication terminals become more popular and are widely being used, increased exposure to electromagnetic waves generated from mobile communication terminals is becoming more prevalent. Accordingly, various studies and measurements have been performed, wherein a specific absorption ratio (SAR), which indicates an amount of electromagnetic radiation generated from mobile communication terminals and absorbed by humans, has been defined. This value is currently being used to regulate electromagnetic wave emissions when manufacturing production mobile communication terminals as well as in the development of new terminals such as IMT-2000 terminals, personal digital assistants (PDA's), and the like.
In some countries, there are standards that regulate the amount of electromagnetic waves generated from mobile terminals to specific levels, and only those mobile terminals that meet this standard may be sold to consumers. Therefore, efforts and research for reducing the exposure to electromagnetic radiation are actively being performed.
FIG. 1 is a perspective view showing the construction of a mobile communication terminal according to the related art. As shown, the mobile terminal comprises: a first folding body 10; a second folding body 22 rotatively connected to the first folding body 10 via a hinge portion 30; and an antenna device 40 protruding away from an upper surface 15b of the body 10.
The first folding body 10 includes: a body case 15 covering a main PCB; a battery 12 mounted at a rear surface of the body case 15; and a camera 18 mounted at a front upper end portion of the body case 15. The second folding body 22 includes: a secondary liquid crystal screen 21 formed on the front surface of the second folding body 22; and a sound wave transmission hole 23 formed at a lower end portion of the front surface of the second folding body 22.
The antenna device 40 is composed of a helical antenna and a whip antenna. As shown in FIG. 2, the helical antenna includes: a bobbin 42 wound by a helical wire 42a in a hollow cylindrical antenna body 41; and a fitting unit 44 for connection to the main PCB of the body 10 and provided with a screw 43. The whip antenna includes: a whip 45 provided with a signal transmitting wire therein; a knob 47 formed at the end of the whip 45; and a stopper 46 for preventing the whip 45 from being completely separated from the body 10. As shown in FIG. 3, the screw 43 is coupled to a bushing 15a of a conductive material mounted in the rear of the body case 15.
An operation of the related art antenna apparatus of the mobile terminal will be explained as follows. When the mobile communication terminal is in a call standby state, generally the whip antenna 45 is recessed and only the helical antenna of the antenna device 40 is used. If a user extracts the whip 45, such as by pulling on the knob 47 when making or receiving a call, the helical antenna is not used and, instead, only the whip antenna is used. Herein, the whip 45 is extracted until the stopper 46 comes into contact with the fitting unit 44. The signal transmitting wire mounted in the whip 45 transfers the received signals to the main PCB of the body 10 to thereby enable mobile communications.
However, the related art antenna device 40 fixed to the terminal body remains proximate to the user's person, generally the head, when the mobile communication terminal is in use. Since electromagnetic waves generated from the antenna device 40 are emitted in a direction perpendicular to the antenna device 40, electromagnetic waves from the related art antenna device 40 are emitted towards the user.